Question Author
Thanks for the advice, rowanwitch.
Of course water butts would not have done me much good this year! Without being brash, I'm not really strapped for cash and I'll just pay for what I use. But the water industry annoys me because it has made it its business to discourage use of its (one and only) product whilst trying to suggest it is a "normal" business. They've made no efforts to expand their storage, production or distribution facilities whilst allowing vast quantities of their product to leak away.
You could well be right Togo. But they'll have difficulty discriminating by area because, unlike water (which should have one), energy has a National grid. Most of the UK's energy problems stem from government and EU mismanagement of the business.